Laparoscopic surgery, also known as minimal access, minimally invasive or keyhole surgery, is a modern surgical technique. During laparoscopic surgery operations are performed through small incisions, usually 0.5 to 1.5 cm in length. This is in contrast to traditional open surgery where a much longer incision would be made to perform the same operation.
Minimal access surgery also known as minimally invasive surgery (MIS) which includes laparoscopic and robotic surgery and which utilises minimal sized incisions is becoming increasingly popular, with more and more routine operations such as nephrectomy and cystectomy being carried out with this type of surgery.
Laparoscopic and robotic surgery have many advantageous over traditional surgery, which are mainly due to the minimally invasive nature and small incision length. These advantages include reduced pain, reduced blood loss, reduced scarring, fewer post-operative infections and shorter recovery times.
However, one of the limitations of MIS concerns the removal of a relatively large specimen. This is particularly common in oncological procedures such as laparoscopic radical nephrectomy, colectomy, cystectomy and hysterectomy. In most oncological and many other laparoscopic procedures, the specimen to be removed from the patient's body is too large to be able to remove it easily through the normal incision made for a laparoscopic port (called a port incision). In this situation the surgeon currently has two options.
The first option is to make a further, larger, incision or to enlarge the port incision so that the specimen can be removed as a whole. Usually this requires an incision of 10 cm long or longer, and sometimes the incision can be longer than 20 cm. Hence, this reduces the advantages of using laparoscopic surgery, which are listed above, and in some cases means that there is actually minimal benefit in performing laparoscopic surgery, over traditional open surgery.
The second option is to morcellate the specimen inside the body cavity into pieces that are small enough to be removed through the port incision. A major concern with this approach is that it is not always possible to ensure that every trace of the morcellated specimen is removed. Where the specimen is benign, leaving a part of the specimen in the body cavity may lead to infection as the tissue breaks down and acts as a source for infection. There is even more risk involved in this method when the specimen is malignant, since any escape of malignant cells can lead to tumour seeding. Tumour seeding can occur at the site from which the specimen is removed. In addition, since the surgical plume travels throughout the surgical site, metastasis can occur at any point where ‘raw’ areas are located, such as any of the port sites. In view of these risks, most large specimens are still extracted in one piece through a separate incision.
There have, however, been some attempts to reduce the risks associated with morcellating the specimen inside the body cavity, by placing a bag around the specimen before it is morcellated. Such a device is generally known as an Endo-Bag. Endo-Bags normally comprise a plastic bag, with an opening at one end. They are inserted through the port incision, the specimen is then passed into the bag and can be pulled through the incision in the bag, optionally after being cut up. Some Endo-Bags, such as that shown in U.S. Pat. No. 6,270,505 comprise a plastic tube with an opening at both ends. A drawstring is provided at one end, which is closed once the specimen is inside the tube. The most common type of morcellation is via a blunt instrument which crushes the tissue and it is then pulled out in pieces through the port incision.
While the use of Endo-Bags can reduce the risks, Endo-Bags do not enclose the whole surgical plume, particularly when they are closed only by means of a drawstring at one end. Therefore, the risk of tumour seeding and port site metastasis remains. In addition, Endo-Bags are normally made from one or two layers of a thin flexible film of a polymer such as polyethylene or polyurethane. These can be ruptured by a sharp instrument, including those needed to morcellate the specimen. This possibility also presents the danger of tumour seeding.
The present invention is concerned with addressing these problems and with providing an improved solution for the removal of large specimens during laparoscopic surgery. In particular, the present invention aims to provide a method of laparoscopic surgery which allows for morcellation of a specimen inside the body cavity, with a reduced risk of tumour seeding.